Engineered by Honda for the sport touring motorcycle segment, the 1984 Honda CB 650 SC Nighthawk relies on a 655 cc (40 cu in) air-cooled in-line four, four-stroke powerplant. In factory specification, peak output is rated at 63 HP (46 kW), transferring power to the rear wheel through a 6-speed gearbox and shaft drive (cardan) final drive. With a specific output of 96.2 HP per liter, the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.
On the scales, the CB 650 SC Nighthawk measures 197 kg (434 lbs) dry, translating to a power-to-weight ratio of 0.32 HP/kg (3.13 kg per horsepower). Rider ergonomics and chassis geometry center around a 790 mm (31.1 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,461 mm (57.5 in) wheelbase engineered for balanced agility and highway composure. The 12.86-liter (3.4 US gal) fuel tank paired with a rated consumption of 5.88 L/100 km provides an estimated theoretical range of roughly 219 km (136 miles) between fill-ups, while factory top speed is listed at 175 km/h (109 mph).
Within MotoLibrary's Honda archive, this model family spans 2 indexed model years from 1983 to 1984, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
96.2 HP/L
Power-to-Weight
0.32 HP/kg (3.13 kg/HP)
Theoretical Range
~219 km (136 mi)
Engine
Displacement655.0 ccm (39.97 cubic inches)
Engine TypeIn-line four, four-stroke
Engine DetailsIn-line four, four-stroke
Power63.0 HP (46.0 kW))
Compression9.5:1
Bore x Stroke60.0 x 58.0 mm (2.4 x 2.3 inches)
Valves/Cylinder4
Fuel SystemCarburettor. Four 32mm constant velocity
Fuel ControlDouble Overhead Cams/Twin Cam (DOHC)
IgnitionSolid state
CoolingAir
Max RPM10000
Transmission
Gearbox6-speed
Final DriveShaft drive (cardan) (final drive)
Clutchhydro activated clutch
Performance
Top Speed175.0 km/h (108.7 mph)
Fuel Consumption5.88 litres/100 km (17.0 km/l or 40.00 mpg)
Greenhouse Gases136.4 CO2 g/km. (CO2 - Carbon dioxide emission)
ExhaustDouble 4 into 2 with crossover
Chassis
Front SuspensionAir-adjustable, leading-axle forks with dual Syntallic bushings
Rear Suspensionadustable daul shock
Wheelbase1461 mm (57.5 inches)
Ground Clearance145 mm (5.7 inches)
Wheels & Brakes
Front BrakesDouble disc. daul disc twin piston calipers
Rear BrakesExpanding brake (drum brake)
Dimensions & Weight
Dry Weight197.0 kg (434.3 pounds)
Power/Weight0.3198 HP/kg
Seat Height790 mm (31.1 inches) If adjustable, lowest setting.
Alt. Seat Height790 mm (31.1 inches) If adjustable, highest setting.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
